* {
    margin:0;
    padding:0;
}
.box {
    width:350px;
    height:262px;
    margin:30px;
    border:1px solid #ccc;
    position:relative;
}
.big {
    width:400px;
    height:400px;
    position:absolute;
    top:0;
    left:360px;
    border:1px solid #ccc;
    overflow:hidden;
    display:none;
}
.mask {
    width:175px;
    height:175px;
    background:rgba(255,255,0,0.4);
    position:absolute;
    top:0;
    left:0;
    cursor:move;
    display:none;
}
.small {
    position:relative;
}
.box img {
    vertical-align:top;
}
#bigBox img {
    position:absolute;
}